LHC team finds new type of boson

Emma Woollacott, 23rd December 2011

Well, it may not be the elusive Higgs boson, but scientists monitoring the ATLAS experiment at the Large Hadron Collider say they've clear evidence of one new particle at least.

The chi b(3P) boson is a heavier variant of a previously-known particle, but represents a new way of combining a beauty quark and its antiquark so that they bind together.

It's been predicted by many theorists, but has never before been seen.

"While people are rightly interested in the Higgs boson, which we believe gives particles their mass and may have started to reveal itself, a lot of the mass of everyday objects comes from the strong interaction we are investigating using the chi b," says Professor Roger Jones, head of the Lancaster ATLAS group.

Unlike the Higgs, the chi b(3P) isn't made up of smaller particles, but is a combination of two very heavy objects which are held together by the same strong nuclear force which holds the atomic nucleus together.

"Analysing the billions of particle collisions at the LHC is fascinating," says Andy Chisholm, a PhD student from the University of Birmingham who worked on the analysis.

"There are potentially all kinds of interesting things buried in the data, and we were lucky to look in the right place at the right time."

"The lighter partners of the chi b(3P) were observed around twenty five years ago," says Dr Miriam Watson, a research fellow working in the Birmingham group.

"Our new measurements are a great way to test theoretical calculations of the forces that act on fundamental particles, and will move us a step closer to understanding how the universe is held together."